Centrifugal Compressor and Air Conditioning Equipment

ABSTRACT

The present disclosure relates to a centrifugal compressor and air conditioning equipment. The centrifugal compressor includes: a main shaft; a diffuser, provided with a first thrust bearing at one end away from a diffusion surface; a supporting assembly, provided with a second thrust bearing at one end facing towards the diffuser; and a thrust disk, configured to rotate together with the main shaft, located between the diffuser and the supporting assembly along an axial direction and provided with a thrust portion, a clearance between one side of the thrust portion and the first thrust bearing and a clearance between the other side of the thrust portion and the second thrust bearing being limited through mutual abutting of the diffuser and the supporting assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a National Stage of International ApplicationNo. PCT/CN2019/113018 filed on Oct. 24, 2019, which claims the priorityof the Chinese patent application No. 201811593330.0, entitled“CENTRIFUGAL COMPRESSOR AND AIR CONDITIONING EQUIPMENT” and filed onDec. 25, 2018, both of which are incorporated herein by reference intheir entireties.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to the technical field of air compressionequipment, and in particular, to a centrifugal compressor and airconditioning equipment.

Description of Related Art

A dynamic pressure gas bearing has the advantages of high precision, lowfriction loss, long life, low vibration, no pollution and no need ofproviding a lubricating medium, etc. Meanwhile, the dynamic pressure gasbearing is suitable for occasions with high rotating speed and highprecision, and has a wide application prospect in centrifugalcompressors, especially small centrifugal compressors. However, theclearance of the gas bearing is very small, only several microns or eventens of microns, and the machining precision of parts is required to besub-micron. Therefore, it is very important to ensure a thrust surfaceclearance of the thrust bearing. If the clearance is controlledinaccurately, the performance of the thrust bearing will be reduced, andin severe cases, the bearing will fail.

SUMMARY OF THE DISCLOSURE

One aspect of embodiments of the present disclosure provides acentrifugal compressor, including:

a main shaft;

a diffuser, provided with a first thrust bearing at one end away from adiffusion surface;

a supporting assembly, provided with a second thrust bearing at one endfacing towards the diffuser; and

a thrust disk, configured to rotate together with the main shaft,located between the diffuser and the supporting assembly along an axialdirection and provided with a thrust portion, a clearance between oneside of the thrust portion and the first thrust bearing and a clearancebetween other side of the thrust portion and the second thrust bearingbeing limited through mutual abutting of the diffuser and the supportingassembly.

In some embodiments, a first groove is formed at one end, away from thediffusion surface, of a diffuser; a first thrust bearing is arranged atthe bottom of the first groove along the axial direction; and a thrustportion is located in the first groove.

In some embodiments, the centrifugal compressor further includes a shelland a radial bearing, wherein the supporting assembly includes:

a fixing plate, provided with the second thrust bearing on one sidefacing towards the diffuser; and

a bearing support, arranged one side, away from the diffuser, of thefixing plate, a first end of the bearing support being connected to thefixing plate, and a second end of the bearing support being connected toa shell and configured to supporting a main shaft through a radialbearing.

In some embodiments, a fixing plate and a bearing support form anintegrated structure.

In some embodiments, a fixing plate is configured to limit adisplacement of a radial bearing towards one side of a diffuser along anaxial direction.

In some embodiments, a locating ring is arranged at one end, facingtowards a bearing support, of a fixing plate; the bearing support isprovided with a second annular groove; the locating ring is arrangedinto the second groove; and an inner wall of the locating ring engageswith an outer wall of a partial length section of a radial bearing.

In some embodiments, the centrifugal compressor further includes a shelland a radial bearing, wherein the supporting assembly includes:

a bearing support, connected to the shell, a second thrust bearing beingarranged on one side, facing towards a diffuser, of the bearing support,and the bearing support being configured to support a main shaft throughthe radial bearing.

In some embodiments, the centrifugal compressor further includes a shelland a radial bearing, wherein the supporting assembly includes a bearingsupport, a first end of the bearing support abutting against diffuser, asecond end of the bearing support being connected to the shell andconfigured to support a main shaft through the radial bearing, andradial outline dimensions of the bearing support gradually increasingfrom the first end to the second end thereof.

In some embodiments, the centrifugal compressor further includes aradial bearing, wherein the supporting assembly includes a bearingsupport configured to support a main shaft through the radial bearing,the bearing support being provided with a vent hole configured tocommunicate a space where the radial bearing is located with a spacewhere the first thrust bearing and the second thrust bearing arelocated.

In some embodiments, a first thrust bearing is directly fixed at thebottom of a first groove.

In some embodiments, the centrifugal compressor further includes animpeller and a locking part, wherein the main shaft is internallyprovided with a cavity and is provided with a shaft core at the center,an end of the shaft core extending out of an end of the main shaft; andthe impeller sleeves an outer end of the shaft core and locks theimpeller on the shaft core through the locking part, and the impeller islocated on an outer side of the diffuser.

In some embodiments, the thrust disk further includes a connectionportion, wherein the connection portion is connected to the thrustportion and sleeves the main shaft; a through hole is provided at thebottom of the first groove; and the connection portion is arranged intothe through hole.

In some embodiments, the centrifugal compressor further includes asealing structure and an impeller on an end of the main shaft, whereinthe impeller is located on an outer side of the diffuser, and thesealing structure adopts at least one of the following structures:

a first axial comb-tooth sealing structure, arranged on a side wall ofthe through hole;

a radial comb-tooth sealing structure, arranged on an end part, facingtowards the diffuser, of the impeller; and

a second axial comb-tooth sealing structure, wherein the impeller isprovided with an protruding portion arranged into the diffuser, and thesecond axial comb-tooth sealing structure is arranged on the protrudingportion along the axial direction.

In some embodiments, the sealing structure simultaneously includes: afirst axial comb-tooth sealing structure, and a radial comb-toothsealing structure and a second axial comb-tooth sealing structure whichare arranged at the same time, wherein the radial comb-tooth sealingstructure is located between the first axial comb-tooth sealingstructure and the second axial comb-tooth sealing structure along aradial direction.

In some embodiments, the centrifugal compressor further includes aradial bearing configured to support a main shaft. At least one of thefirst thrust bearing, the second thrust bearing and the radial bearingis an air-suspending bearing.

Another aspect of embodiments of the present disclosure provides airconditioning equipment, including the centrifugal compressor accordingto the above embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide further understanding ofthe present disclosure and constitute a part of the present disclosure.The exemplary embodiments of the present disclosure and the descriptionthereof serve to explain the present disclosure, but do not constitutean improper limitation to the present disclosure. In the accompanyingdrawings:

FIG. 1 is a structural schematic diagram of some embodiments of acentrifugal compressor according to the present disclosure;

FIG. 2 is a schematic diagram of a mounting structure of a diffuser, athrust disk and a fixing plate in a centrifugal compressor according tothe present disclosure;

FIG. 3 is a schematic diagram of a mounting structure of a diffuser, athrust disk, a fixing plate and a bearing support in a centrifugalcompressor according to the present disclosure;

FIG. 4 is a schematic diagram of an integrated structure of a fixingplate and a bearing support in a centrifugal compressor according to thepresent disclosure;

FIG. 5 is a schematic diagram of a mounting structure of a bearingsupport and a shell in a centrifugal compressor according to the presentdisclosure; and

FIG. 6 is a structural schematic diagram of some embodiments of asealing structure in a centrifugal compressor according to the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure is described hereinafter in detail. In thefollowing paragraphs, different aspects of embodiments are defined indetail. The aspects defined may be combined with one or more of anyother aspects unless it is explicitly pointed that they cannot becombined. In particular, any features considered to be preferred orfavorable may be combined with one or more of other features consideredto be preferred or favorable combination.

The terms “first”, “second” and the like appearing in the presentdisclosure are only used to facilitate description so as to distinguishdifferent components with the same name, but not to represent a sequenceor a primary and secondary relationship.

To clearly describe each azimuth in the following embodiments, anazimuth or position relationship indicated by terms “upper”, “lower”,“top”, “bottom”, “front”, “rear”, “inner”, “outer” and the like isdescribed only for facilitating the description of the presentdisclosure, but not for indicating or implying that the referred devicemust have a specific azimuth and perform construction and operation inthe specific azimuth; therefore, it cannot be interpreted as alimitation to the protection scope of the present disclosure.Furthermore, as shown in FIG. 1, “axial direction”, “circumferentialdirection” and “radial direction” mentioned hereafter are all defined onthe basis of a main shaft 1.

Embodiments of the present disclosure provide a centrifugal compressorand air conditioning equipment, thus improving the assembling precisionof a thrust bearing in the compressor.

To make those skilled in the art understand the improvement points ofthe present disclosure more clearly, the overall structure of thecentrifugal compressor is described with reference to FIG. 1.

As shown in FIG. 1, by taking a two-stage centrifugal compressor as anexample, the compressor includes a first volute 61, a second volute 63and a middle shell 62, wherein the first volute 61 and the second volute63 are respectively arranged at two ends of the middle shell 62 is alongthe axial direction to jointly form a compressor shell 6. A main shaft 1is arranged at the center position of the compressor shell 6, animpeller 2 is arranged at each of two ends of the main shaft 1, and adiffuser 3 is arranged at an inner end of the impeller 2. When theimpellers 2 rotate at a high speed, gas rotates along with the impellers2, the gas is thrown into the diffuser 3 under a centrifugal force,velocity energy of an outlet medium of the impellers 2 is converted intopressure energy, and the gas is discharged from the volutes afterpressure is increased.

To support the main shaft 1, radial bearings 8 are arranged at two endsof the main shaft 1, the radial bearings 8 perform supporting through abearing support 52, and the bearing support 52 is connected to themiddle shell 62. A stator assembly 7 is arranged between the main shaft1 and the middle shell 62. Since each of the impellers 2 will generatean axial force, a thrust bearing is arranged at one end of the mainshaft 1 to balance the axial force generated by the impellers 2.

The working principle of the compressor is: in the working process ofthe compressor, the main shaft 1 rotates at a high speed, gas enters thediffuser 3 through the impeller 2 on the left side, the gas enters thefirst volute 61 after being subjected to primary compression, an exhaustchannel in the first volute 61 guides the compressed gas into theimpeller 2 on the right side, the gas enters the diffuser 3 on the rightside after being centrifuged by the impeller 2 on the right side, thegas enters the second volute 63 after being subjected to secondarycompression, and the gas is discharged out of the compressor through anexhaust channel in the second volute 63.

Then, a bearing supporting assembly in the centrifugal compressor isdescribed in detail. In some embodiments, as shown in FIG. 2, thecentrifugal compressor includes: a main shaft 1, an impeller 2, adiffuser 3, a thrust disk 4 and a supporting assembly 5.

Wherein the main shaft 1 is provided with magnetic steel 13 along amiddle position of the axial direction; the diffuser 3 is fixed on theshell 6; a first thrust bearing 10 is arranged at one end, away from adiffusion surface, of the diffuser 3; and the diffusion surface is anend face closed to the impeller 2. The supporting assembly 5 is arrangedat one end, away from the diffusion surface, of the diffuser 3. One endof the supporting assembly 5 is fixed with the shell 6 of thecompressor, and the other end of the supporting assembly 5 abuts againstan end face of the diffuser 3. A second thrust bearing 10′ is arrangedon one side, facing towards the diffuser 3, of the supporting assembly5. The thrust disk 4 is fixed with the main shaft 1 and is configured torotate together with the main shaft 1. The thrust disk 4 is providedwith a thrust portion 41, for example, a disk-shaped structure. Aclearance between one side of the thrust portion 41 and the first thrustbearing 10 and a clearance between the other side of the thrust portion41 and the second thrust bearing 10′ are limited through mutual abuttingof the diffuser 3 and the supporting assembly 5. Specifically, left andright surfaces of the thrust portion 41 and the thrust bearings on twosides form working surfaces, which may withstand bidirectional axialforces, thus ensuring operational stability and reliability of thecompressor under full working conditions and during reverse rotation.

For example, the first thrust bearing 10 and the second thrust bearing10′ are static pressure or dynamic pressure gas thrust bearings, ormagnetic levitation bearings.

By taking FIG. 2 as an example, since there is a clearance between thethrust bearing and the thrust disk 4, gas will form a gas film with apressure in the clearance for thrusting and lubricating. Since thethrust bearing itself is in a cavity of the compressor and the cavity isfull of the gas, the gas may be brought into the clearance to form adynamic pressure gas thrust bearing in the rotation process of therotor.

In the centrifugal compressor of the embodiment, the thrust diskcooperates with the thrust bearings on the two sides, which may bearaxial forces in left and right directions, thus ensuring the operationstability of the compressor under full working conditions and duringreverse rotation. The operation working conditions of the compressorrefer to an evaporation temperature and a condensation temperature of asystem where the compressor is located. The full working conditionsrefer to that the compressor works within a certain evaporationtemperature range and a condensation temperature range. When thecompressor is shut down, since an exhaust pressure is higher than asuction pressure, the compressor will rotate reversely after shutdown.

Furthermore, the diffuser 3 and the supporting assembly 5 need to befixed on the shell 6 of the compressor, so the own position is fixed.The supporting assembly 5 and the diffuser 3 abut against each other forcombined limitation, thus limiting the position of the thrust disk 4 andthe clearances of the thrust bearings on the two sides. Therefore, theworking clearance of the thrust bearings may be accurately ensured, theassembling difficulty is reduced, the assembling efficiency and theassembling precision are improved, and the working performance of thecompressor is improved, thereby improving the operation stability of thecompressor.

As shown in FIG. 2, a first groove 31 is formed at one end, away from adiffusion surface, of a diffuser 3, a first thrust bearing 10 isarranged at the bottom of the first groove 31 along the axial direction,a thrust portion 41 is located in the first groove 31, and there are aclearance between the one side of the thrust portion 41 and the firstthrust bearing 10 and a clearance between the other side of the thrustportion 41 and the second thrust bearing 10′.

Since the diffuser 3 and the supporting assembly 5 abut against eachother, such that the clearances of the thrust bearings on two sides maybe accurately ensured through an axial depth of the first groove 31, theassembling precision may be improved, the assembling difficulty isreduced, the assembling efficiency is improved, the performance of thethrust bearing can be ensured, and reduction, even failure of theperformance of the thrust bearing caused by inaccurate clearance controlis avoided, thus improving the operation stability of the compressor.

As shown in FIG. 2, a depth of the first groove 31 includes: a thicknessof the thrust portion 41, a total thickness of the thrust bearings ontwo sides and the clearances of the thrust bearings on two sides;therefore, to ensure the clearances of the thrust bearings on two sides,the clearances may be controlled by the depth of the first groove 31,the thickness of the thrust portion 41 and the thicknesses of the thrustbearings on two sides. The specific method is: a design depth and atolerance range of the first groove 31 are derived according to aclearance range which the thrust bearings need to reach, a thicknesstolerance range of the thrust portion 41 and a thickness tolerance rangeof the thrust bearings. Therefore, clearances between the thrustbearings can be ensured by improving the machining precision of thedepth of the first groove 31, the assembling precision may be improvedand the assembling difficulty is reduced, thus improving the assemblingefficiency.

In some embodiments, as shown in FIG. 2 and FIG. 3, the centrifugalcompressor further includes a shell 6 and a radial bearing 8 configuredto bear a radial force of a rotor, wherein the radial force of the rotormainly comes from the gravity of the rotor. For example, the radialbearing 8 is a static pressure or dynamic pressure gas radial bearing,or a magnetic levitation bearing.

The supporting assembly 5 includes a fixing plate 51 and a bearingsupport 52, wherein the fixing plate 51 abuts against the diffuser 3,and the second thrust bearing 10′ is arranged on one side, facingtowards the diffuser 3, of the fixing plate 51; and the bearing support52 is arranged on one side, away from the diffuser 3, of the fixingplate 51, a first end of the bearing support 52 is connected to thefixing plate 51, and a second end of the bearing support 52 is connectedto the shell 6, the bearing support 52 is configured to support a mainshaft 1 through the radial bearing 8.

In this embodiment, the supporting assembly 5 adopts a split structure,the second thrust bearing 10′ is mounted through the fixing plate 51,and the radial bearings 8 are mounted on the bearing support 52, suchthat the mounting position precision, including the coaxiality of thetwo radial bearings 8 and the perpendicularity of the thrust bearings,of the radial bearings 8 at two ends of the main shaft 1 and the thrustbearings may be improved, and the working stability of the rotor systemmay be improved.

As shown in FIG. 5, a flange disk 525 is arranged at a second end of thebearing support 52, a spigot 527 is formed at an outer end of the flangedisk 525, the bearing support 52 is mounted in a middle shell 62 throughthe flange disk 525 and is fixed through a fastener 32, and the bearingsupport 52 is radially located by the spigot 527.

During machining, the two bearing supports 52 are assembled in themiddle shell 62 through first location of the spigot 527 firstly, thenthe flange disk 525 and the middle shell 62 are fixed through thefasteners 32, and a pin is punched for fixation. Then, the middle shell62 and the two bearing supports 52, serving as an whole assembly, arelocated on machining equipment, and end faces, contacting with thefixing plates 51, of the two bearing supports 52 are machined to ensurethe perpendicularity of the thrust bearings and the radial bearings 8,and mounting holes 522 of the two bearing supports 52 are machinedsequentially from one side to ensure the coaxiality of the two radialbearings 8.

After machining, the bearing supports 52 are disassembled, each theradial bearing 8 is mounted into the mounting holes 522 of the bearingsupports 52 through a hot mounting manner, and then the fixing plate 51are mounted at a first end of the bearing support 52. The bearingsupports 52 are fixedly mounted on the shell 6 through the position ofthe pin determined during machining.

Since each key locating part is machined in one clamping process, thecoaxiality of the two radial bearings 8 and the perpendicularity of thethrust bearings may be ensured, thus improving the working stability ofthe rotor system.

As shown in FIG. 3, the fixing plate 51 is further configured to limit adisplacement of each of the radial bearings 8 towards one side of thediffuser 3 along the axial direction; therefore, the fixing plate 51 iscapable of mounting the second thrust bearing 10′ and also capable ofaxially limiting the radial bearings 8, such that the structure of thebearing supporting assembly may be more compact, and it is beneficial toensure a parallelism of a mounting surface of the second thrust bearing10′ and an axial limiting surface of each of the radial bearings 8through a machining parallelism of two sides of the fixing plate 51,thus improving the mounting precision of the thrust bearing and theradial bearings 8.

In some embodiments, a locating ring 511 is arranged at one end, facingtowards the bearing support 52, of the fixing plate 51, the bearingsupport 52 is provided with an annular second groove 521, the locatingring 511 is arranged into the second groove 521 to radially locate thefixing plate 51, and there is a clearance between the fixing plate 51and the main shaft 1. Furthermore, an inner wall of the locating ring511 engages with an outer wall of a partial length section of the radialbearing 8 for supporting the partial length section of the radialbearing 8 and playing an axial thrust role in the radial bearing 8.

In some embodiments, as shown in FIG. 2, the first thrust bearing 10 isfixed on the diffuser 3 through a fastener 32, the second thrust bearing10′ is fixed on the fixing plate 51 through the fastener 32, the fixingplate 51 and the diffuser 3 abut against each other, and a spigot 33 isformed at the periphery of the diffuser 3, thereby facilitating locationand mounting of a shell 6.

In some embodiments, as shown in FIG. 4, a fixing plate 51 and a bearingsupport 52 form an integrated structure. The supporting assembly 5adopts an integrated structure, such that the structure may besimplified, the assembly difficulty may be reduced, and it is easy toensure the perpendicularity of the radial bearing 8 and the thrustbearing through the machining precision of the supporting assembly 5.

In some embodiments, referring to FIG. 4, the centrifugal compressorfurther includes a shell 6 and a radial bearing 8. The supportingassembly 5 includes a bearing support 52, wherein a first end of thebearing support 52 abuts against a diffuser 3 and a second end of thebearing support 52 is connected to the shell 6; the second thrustbearing 10′ is arranged on one side, facing towards the diffuser 3, ofthe bearing support 52; and the bearing support 52 is further configuredto support a main shaft 1 through the radial bearing 8. A thrustplatform is reserved on the bearing support 52 when a mounting hole 522is machined so as to axially limit the radial bearing 8.

Compared with the embodiment as shown in FIG. 4, a fixing plate 51 isomitted, such that an axial size of the bearing supporting assembly maybe further reduced, the structure can be simplified, the assemblingdifficulty is reduced, and it is easy to ensure the perpendicularity ofthe radial bearing 8 and the thrust bearing through the machiningprecision of the supporting assembly 5.

As shown in FIG. 3 and FIG. 4, the centrifugal compressor furtherincludes a shell 6 and a radial bearing 8. The supporting assembly 5includes a bearing support 52, wherein a first end of the bearingsupport 52 abuts against a diffuser 3, and a second end of the bearingsupport 52 is connected to the shell 6 for supporting a main shaft 1through the radial bearing 8. Since an outer diameter of the thrustbearing is less than an inner diameter of the shell 6, accordingly,outline dimensions of the bearing support 52 in a longitudinal sectiongradually increase from the first end to the second end, that is, radialoutline dimensions of the bearing support 52 gradually increase from thefirst end to the second end thereof. To reduce the weight, as shown inFIG. 5, a weight-reducing groove 524 is formed in one side, away fromthe thrust bearing, of the bearing support 52, for example, theweight-reducing groove 524 is arranged annularly, an inner wall of theweight-reducing groove 524 is parallel to a side wall of the mountinghole 522, and an outer wall of the weight-reducing groove 524 isconsistent with an overall shape of the bearing support 52.

The V-shaped bearing support 52 adopts a structure with gradually variedcross sectional area, such that the overall structural strength of thebearing support 52 may be improved, stress in all places is distributeduniformly and the bearing capacity may be optimized; moreover, an outerside wall is an inclined surface which is easily realized by casting,and has a draft angle when being cast by a mold.

As shown in FIG. 5, the bearing support 52 is provided with a vent hole526 configured to communicate a space where the radial bearing 8 islocated with a space where the first thrust bearing 10 and the secondthrust bearing 10′ are located, such that the working environment of theradial bearing 8 is consistent with those of the first thrust bearing 10and the second thrust bearing 10′, for example, the working backpressure of the radial bearing 8 is consistent with those of the firstthrust bearing 10 and the second thrust bearing 10′. A refrigerant forcooling a motor enters and exits a motor cavity, when the compressoroperates normally, pressure and temperature of the overall motor cavityare stable, the working environment of the thrust bearing and the radialbearing is as same as that of the motor cavity, that is, gas circulationis ensured, the back pressure is relatively stable, and fluctuation of abearing gas film caused by too large fluctuation is reduced, thusimproving the performance of the bearing.

As shown in FIG. 3, the bearing support 52 is provided with an operatinghole 523 along a radial direction, such that a vibration sensor or atemperature sensor is mounted on an outer wall of the radial bearing 8through the operating hole 523 to monitor the working state of theradial bearing 8. A hole section of the operating hole 523 along aradial outer side serves as a bypass hole so as to ensure that thepressure and temperature of the thrust bearing and the radial bearing 8are as same as those of the motor cavity; and a hole section of theoperating hole 523 along a radial inner side serves to dissipate heatfor the radial bearing 8.

In some embodiments, as shown in FIG. 3, the first thrust bearing 10 isdirectly fixed at the bottom of the first groove 31 of the diffuser 3.For example, the first thrust bearing 10 adopts a dynamic pressurethrust bearing which is a flaky structure. The dynamic pressure thrustbearing is directly fixed at the bottom of the first groove 31.According to the structure, the diffuser 3 and the fixing plate of thethrust bearing are integrated into a part, the bottom of the firstgroove 31 may serve as the fixing plate of the first thrust bearing 10without additionally setting the fixing plate of the thrust bearing,such that an axial size of the bearing supporting assembly may befurther reduced and the structure is more compact.

In some embodiments, as shown in FIG. 1, the centrifugal compressorfurther includes an impeller 2 and a locking part 9, wherein the mainshaft 1 is internally provided with a cavity 11 and is provided with ashaft core 12 at the center, an end of the shaft core 12 extending outof an end of the main shaft 1; and the impeller 2 sleeves an outer endof the shaft core 12 and locks the impeller 2 on the shaft core 12through the locking part 9, and the impeller 2 is located on an outerside of the diffuser 3.

According to this embodiment, the impeller 2 may be detachably arrangedrelative to the main shaft 1, such that the assembling and disassemblingdifficulty of the impeller may be reduced, the assembling process of theimpeller and the required equipment are simplified, and the assemblingefficiency and the operability of the disassembling and inspection workand maintenance are improved. Furthermore, the mounting mode can preventthe main shaft 1 or the impeller 2 from being deformed, may ensure themounting strength of the impeller 2 and may avoid stress concentration,thus improving the compression capacity of the compressor. In addition,the cavity 11 is formed in the main shaft 1, such that the weight of themain shaft 1 may be reduced, thus increasing the critical rotating speedof the main shaft 1 and further improving the ultimate working capacityof the compressor.

Still referring to FIG. 1, the shaft core 12 is directly formed when thecavity 11 is machined, such that the shaft core 12 and the rest part ofthe main shaft 1 are machined into a whole body, it is unnecessary toadditionally mount the shaft core 12 in the cavity of the main shaft 1,the assembling difficulty may be further reduced, the connectionstrength of the shaft core 12 and the main shaft 1 is improved, theposition precision of the shaft core 12 may be ensured, the bounceproblem of the front end of the rotor is effectively solved, and thelength of a cantilever end is reduced, thus improving the workingstability and reliability of the compressor. For example, the cavity 11is a ring groove, or a plurality of holes which are symmetrical relativeto the center of an axis.

As shown in FIG. 3, the thrust disk 4 further includes a connectionportion 42, wherein the connection portion 42 is connected to the thrustportion 41 and sleeves the main shaft 1; a through hole 34 is formed atthe bottom of the first groove 31; and the connection portion 42 isarranged into the through hole 34. The connection portion 42 is ininterference fit with the main shaft 1, such that the thrust disk 4 mayrotate together with the main shaft 1. The diffuser 3 and the fixingplate 51 are fixedly arranged, and there is a clearance between thediffuser 3 and the main shaft 1. For example, the thrust disk 4 has acylindrical stepped structure.

As shown in FIG. 6, the centrifugal compressor further includes asealing structure and an impeller 2 arranged on an end of the main shaft1, wherein the impeller 2 is located on an outer side of the diffuser 3.In some embodiments, a first axial comb-tooth sealing structure 35 isarranged on a side wall of the through hole 34 and forms a shaft sealwith the thrust disk 4, thus reducing refrigerants from entering a motorcavity through the clearance between the diffuser 3 and the thrust disk4 along with the exhaust of the impeller. In some embodiments, a radialcomb-tooth sealing structure 21 is arranged on an end, facing towardsthe diffuser 3, of the impeller 2, thus reducing refrigerants fromflowing towards the periphery along with the clearance between theimpeller 2 and the diffuser 3. In some embodiments, the impeller 2 isprovided with an protruding portion 22 arranged into the diffuser 3, forexample, the protruding portion 22 is of an elongated strip structureextending along the axial direction, the protruding portion 22 isprovided with a second axial comb-tooth sealing structure 23 on a radialinner side along a length direction of the protruding portion 22, thusreducing refrigerants from flowing towards the periphery along theclearance between the impeller 2 and the diffuser 3.

In some embodiments, the comb-tooth sealing structure includes aplurality of teeth arranged at intervals, wherein the teeth aretrapezoidal; and one side wall of each tooth is a vertical surface, andthe other side wall of each tooth is an inclined surface and inclinesfrom a high-pressure side to a low-pressure side.

The embodiment can reduce the leakage amount of the refrigerants betweenthe impeller 2 and the diffuser 3 and between the diffuser 3 and thethrust disk 4, can ensure the clearance required for operation of themain shaft 1 and the impeller 2, and also can prevent leakage of therefrigerants caused by too large clearance, thereby effectively solvingthe sealing problem of the compressor and improving the energyefficiency of the compressor.

Moreover, the structure integrates the diffuser 3, the fixing plate ofthe thrust bearing and a shaft sealing part into a part, such that themounting structure may be simplified, the structure is more compact andthe assembling efficiency is improved. As shown in FIG. 2, a spigot 33is formed at the periphery of the diffuser 3 to facilitate location andmounting of the shell 6 and realize accurate location with the pin.Therefore, the coaxiality of the shaft sealing part on the diffuser 3and the perpendicularity of a thrust bearing fixing surface are ensuredon one part, and the machining difficulty and the assembling accumulatederror are reduced. The shaft seal with high requirement on coaxialityand the thrust bearing with high requirement on perpendicularity arelocated jointly by the locating spigot 33 and the pin, the assemblingstandard is unified, the assembling difficulty is reduced and theassembling precision is improved, such that the perpendicularity of thethrust bearing fixing surface can be improved to ensure the workingperformance of the thrust bearing, and the coaxiality of the first axialcomb-tooth sealing structure 35 can be improved to prevent the sealingproperty from being affected by the wear of the comb teeth.

In terms of material section, a material of the diffuser 3 has lowerhardness than the thrust disk 4. Generally, the diffuser 3 adoptsaluminum, and the thrust disk adopts 45 steel or 40 Cr, etc. In thisway, if the first axial comb-tooth sealing structure 35 on the diffuser3 and the main shaft 1 are worn, the comb teeth are worn firstly toprevent the main shaft 1 from being worn.

Still referring to FIG. 6, the sealing structure simultaneously includesa first axial comb-tooth sealing structure 35, a radial comb-toothsealing structure 21 and a second axial comb-tooth sealing structure 23,wherein the radial comb-tooth sealing structure 21 is located betweenthe first axial comb-tooth sealing structure 35 and the second axialcomb-tooth sealing structure 23 along a radial direction. Thisarrangement can make gas flow form a circuitous flow path so as tooptimize the gas flow deceleration and depressurization effect andimprove the sealing property.

Specifically, a boss 24 is arranged at one end, facing towards thediffuser 3, of the impeller 2, the boss 24 stretches into a third groove36 of the diffuser 3, and the radial comb-tooth sealing structure 21 isarranged on an end part of the boss 24, such that the gas flow path isfurther lengthened while radial sealing is realized, the gas flowdeceleration and depressurization effect is optimized, and the sealingproperty is improved.

In addition, the present disclosure further provides air conditioningequipment, including the centrifugal compressor according to the aboveembodiments. The centrifugal compressor provided by the presentdisclosure may bear axial forces in two directions and ensure theoperation stability of the compressor under full working conditions andduring reverse rotation, and is capable of accurately ensuring theassembling clearance between the thrust bearings and ensuring theperformance of the thrust bearings, thereby improving the operationalstability of the compressor. The two factors can improve the workingstability and reliability of the air conditioning equipment.

The centrifugal compressor and the air conditioning equipment accordingto the present disclosure are introduced above in detail. The principleand embodiments of the present disclosure are elaborated by specificembodiments, and the description of the above embodiments is onlyintended to help understand the method of the present disclosure and thecore concept thereof. It should be noted that those skilled in the artmay also make several improvements and modifications without departingfrom the principles of the present disclosure which should fall withinthe protection scope of the claims of the present disclosure.

1. A centrifugal compressor, comprising: a main shaft; a diffuser,provided with a first thrust bearing at one end away from a diffusionsurface; a supporting assembly, provided with a second thrust bearing atone end facing towards the diffuser; and a thrust disk, configured torotate together with the main shaft, located between the diffuser andthe supporting assembly along an axial direction and provided with athrust portion, and a clearance between one side of the thrust portionand the first thrust bearing and a clearance between the other side ofthe thrust portion and the second thrust bearing are limited throughmutual abutting of the diffuser and the supporting assembly.
 2. Thecentrifugal compressor according to claim 1, wherein a first groove isformed at one end, away from the diffusion surface, of the diffuser, thefirst thrust bearing is arranged at the bottom of the first groove alongthe axial direction, and the thrust portion is located in the firstgroove.
 3. The centrifugal compressor according to claim 1, furthercomprising a shell and a radial bearing, wherein the supporting assemblycomprises: a fixing plate, provided with the second thrust bearing onone side facing towards the diffuser; and a bearing support, arranged onone side, away from the diffuser, of the fixing plate, a first end ofthe bearing support being connected to the fixing plate, and a secondend of the bearing support being connected to the shell and configuredto support the main shaft through the radial bearing.
 4. The centrifugalcompressor according to claim 3, wherein the fixing plate and thebearing support form an integrated structure.
 5. The centrifugalcompressor according to claim 3, wherein the fixing plate is configuredto limit a displacement of the radial bearing towards one side of thediffuser along the axial direction.
 6. The centrifugal compressoraccording to claim 5, wherein a locating ring is arranged at one end,facing towards the bearing support, of the fixing plate, the bearingsupport is provided with an annular second groove, the locating ring isarranged into the second groove, and an inner of the locating ringengages with an outer wall of a partial length section of the radialbearing.
 7. The centrifugal compressor according to claim 1, furthercomprising a shell and a radial bearing, wherein the supporting assemblycomprises: a bearing support, connected to the shell, the second thrustbearing being arranged on one side, facing towards the diffuser, of thebearing support, and the bearing support being configured to support themain shaft through the radial bearing.
 8. The centrifugal compressoraccording to claim 1, further comprising a shell and a radial bearing,wherein the supporting assembly comprises a bearing support, a first endof the bearing support abutting against the diffuser, a second end ofthe bearing support being connected to the shell and configured tosupport the main shaft through the radial bearing, and radial outlinedimensions of the bearing support gradually increasing from the firstend to the second end thereof.
 9. The centrifugal compressor accordingto claim 1, further comprising a radial bearing, wherein the supportingassembly comprises a bearing support configured to support the mainshaft through the radial bearing, the bearing support being providedwith a vent hole configured to communicate a space where the radialbearing is located with a space where the first thrust bearing and thesecond thrust bearing are located.
 10. The centrifugal compressoraccording to claim 1, further comprising an impeller and a locking part,wherein the main shaft is internally provided with a cavity and isprovided with a shaft core at the center, an end of the shaft coreextending out of an end of the main shaft and the impeller sleeves anouter end of the shaft core and locks the impeller on the shaft corethrough the locking part, and the impeller is located on an outer sideof the diffuser.
 11. The centrifugal compressor according to claim 2,wherein the first thrust bearing is directly fixed at the bottom of thefirst groove.
 12. The centrifugal compressor according to claim 2,wherein the thrust disk further comprises a connection portion, theconnection portion being connected to the thrust portion and sleevingthe main shaft; and a through hole is provided at the bottom of thefirst groove, and the connection portion is arranged into the throughhole.
 13. The centrifugal compressor according to claim 12, furthercomprising a sealing structure and an impeller arranged on an end of themain shaft wherein the impeller is located on an outer side of thediffuser, and the sealing structure adopts at least one of the followingstructures: a first axial comb-tooth sealing structure arranged on aside wall of the through hole; a radial comb-tooth sealing structurearranged on an end, facing towards the diffuser, of the impeller; and asecond axial comb-tooth sealing structure, wherein the impeller isprovided with an protruding portion arranged into the diffuser, and thesecond axial comb-tooth sealing structure is arranged on the protrudingportion along the axial direction.
 14. The centrifugal compressoraccording to claim 13, wherein the sealing structure comprises: thefirst axial comb-tooth sealing structure the radial comb-tooth sealingstructure and the second axial comb-tooth sealing structure, and theradial comb-tooth sealing structure being located between the firstaxial comb-tooth sealing structure and the second axial comb-toothsealing structure along a radial direction.
 15. The centrifugalcompressor according to claim 1, further comprising a radial bearingconfigured to support the main shaft, wherein at least one of the firstthrust bearing, the second thrust bearing and the radial bearing is anair-suspending bearing.
 16. Air conditioning equipment, comprising thecentrifugal compressor according to claim
 1. 17. The centrifugalcompressor according to claim 2, further comprising a shell and a radialbearing, wherein the supporting assembly comprises: a fixing plate,provided with the second thrust bearing on one side facing towards thediffuser; and a bearing support, arranged on one side, away from thediffuser, of the fixing plate, a first end of the bearing support beingconnected to the fixing plate, and a second end of the bearing supportbeing connected to the shell and configured to support the main shaftthrough the radial bearing.
 18. The centrifugal compressor according toclaim 2, further comprising a shell and a radial bearing, wherein thesupporting assembly comprises: a bearing support, connected to theshell, the second thrust bearing being arranged on one side, facingtowards the diffuser, of the bearing support, and the bearing supportbeing configured to support the main shaft through the radial bearing.19. The centrifugal compressor according to claim 2, further comprisinga shell and a radial bearing, wherein the supporting assembly comprisesa bearing support, a first end of the bearing support abutting againstthe diffuser, a second end of the bearing support being connected to theshell and configured to support the main shaft through the radialbearing, and radial outline dimensions of the bearing support graduallyincreasing from the first end to the second end thereof.
 20. Thecentrifugal compressor according to claim 4, wherein the fixing plate isconfigured to limit a displacement of the radial bearing towards oneside of the diffuser along the axial direction.